**Core Concept**
The question is testing the child's developmental quotient (DQ), which is a measure of a child's cognitive development in relation to their chronological age. The DQ score of 50 indicates a significant delay in cognitive development.

**Why the Correct Answer is Right**
A DQ of 50 corresponds to a mental age of 2.5 years. Children at this age typically begin to develop basic self-care skills, such as dressing and using the toilet. They may also start to show an interest in simple games and activities, but their cognitive abilities are still limited.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because a child with a DQ of 50 would not be able to perform tasks that require complex problem-solving or critical thinking, such as reading and writing.
**Option B:** This option is incorrect because a child with a DQ of 50 would not be able to understand and follow complex instructions or engage in abstract thinking, such as understanding time and schedules.
**Option C:** This option is incorrect because a child with a DQ of 50 would not be able to demonstrate advanced cognitive skills, such as understanding and using money or telling time.

**Clinical Pearl / High-Yield Fact**
Children with significant delays in cognitive development, such as those with a DQ of 50, often require early intervention and special education to help them develop basic skills and reach their full potential.

**Correct Answer: C.** A child with a DQ of 50 can dress and use the toilet, but not perform tasks that require complex problem-solving or critical thinking.